<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>弹性盒子布局</title>
    <style>
        .container {
            display: flex;
            height: 400px;
            width: 600px;
            background-color: #e1e1e1;
            /*flex-direction: column-reverse;*/
            flex-direction: column;
            flex-wrap: wrap;
        }

        .container div {
            background-color: #ffb84d;
            border: 2px solid #666;
        }

        .item1 {
            width: 250px;
        }

        .item2 {
            /*flex: 2;*/
            width: 350px;
            /*flex:2 300px;*/
        }

        .item3 {
            width: 350px
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="item1">one</div>
        <div class="item2">two</div>
        <div class="item3">three</div>
    </div>
</body>
</html>